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Search for "radicals" in Full Text gives 225 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
ZnO nanoparticles sensitized by CuInZnxS2+x quantum dots as highly efficient solar light driven photocatalysts
Beilstein J. Nanotechnol. 2017, 8, 1080–1093, doi:10.3762/bjnano.8.110
- absorption of Orange II at λmax = 485 nm. Detection of •OH radicals: DST assay The production of •OH radicals by ZnO and the ZnO/ZCIS photocatalyst was measured by using disodium terephthalate (DST). DST turns into fluorescent 2-hydroxyterephthalate, 2-OH-DST (λem = 428 nm) upon reaction with an •OH radical
- ]. Detection of O2•− radicals: NBT assay The production of superoxide O2•− radicals was measured using the nitroblue tetrazolium (NBT). The reduction of the yellowish NBT into purple formazan derivatives results in an increase of the absorbance between 450 and 700 nm. The ZnO or ZnO/ZCIS photocatalyst (5 mg
- values were varying from 4.8 for NaH2PO4 to 11.5 for Na3PO4) (Figure 6b). Na2CO3 and NaHCO3 reduced the photodegradation rates probably because these salts may adsorb at the surface of the ZnO/ZCIS catalyst and hinder the adsorption of the Orange II dye or consume •OH radicals. The generated carbonate
Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties
Beilstein J. Nanotechnol. 2017, 8, 933–942, doi:10.3762/bjnano.8.95
- decomposed into radicals by a filament heated to 250–300 °C. The radicals of the initiator selectively react with the vinyl bonds of monomer species absorbed on the substrate, initiating the polymerization. For this, the substrate is typically held below 60 °C. Chain growth then proceeds on the substrate
High photocatalytic activity of Fe2O3/TiO2 nanocomposites prepared by photodeposition for degradation of 2,4-dichlorophenoxyacetic acid
Beilstein J. Nanotechnol. 2017, 8, 915–926, doi:10.3762/bjnano.8.93
- and TiO2 nanoparticles that improved charge transfer and suppressed electron–hole recombination. A further investigation on the role of the active species on Fe2O3/TiO2 confirmed that the crucial active species were both holes and superoxide radicals. The Fe2O3(0.5)/TiO2 sample also showed good
- stability and reusability, suggesting its potential for water purification applications. Keywords: 2,4-dichlorophenoxyacetic acid; Fe2O3/TiO2; herbicide degradation; heterojunction; holes and superoxide radicals; photocatalyst; photodeposition; water purification; Introduction Photocatalytic reactions
- by the photogenerated oxygen radicals [21]. It was demonstrated that the use of the Fe(III) acetylacetonate precursor led to a complete photodeposition to form Fe2O3, as also supported by ICP-OES results discussed above. The improved charge transfer of the Fe2O3(0.5)/TiO2 (PD) sample was further
Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins
Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88
- attributed to the limited penetration depth and diffusion length for ions, radicals and other chemically active species present during plasma etching and ashing, and wet cleans through the overlying hard mask and the interconnected porosity in the organosilicate. More specifically, as the fin dimensions
Vapor deposition routes to conformal polymer thin films
Beilstein J. Nanotechnol. 2017, 8, 723–735, doi:10.3762/bjnano.8.76
- polymer film. As seen in Figure 2b, gas phase monomers containing a reactive bond first adsorb on the substrate near room temperature. An initiator, such as di-tert-butyl peroxide is thermally cleaved by a hot filament (≈250 °C) and the resulting radicals collide with surface adsorbed monomers to initiate
- polymerize upon the impingement of an initiator radical. The initiator radicals are quite volatile and are expected to have negligible adsorption on the bare surface. Additionally, once a monomer undergoes polymerization, it is no longer a site for initiator chemisorption. Therefore, the number surface sites
- sticking probability of the initiator, the same monomer, cyclohexylmethacrylate, was iCVD polymerized holding Pm/Psat fixed using two different initiators [24]. The first initiator was tert-butyl peroxide (TBPO) which decomposes over the heated filament to give two tert-butoxy radicals. The second
α-((4-Cyanobenzoyl)oxy)-ω-methyl poly(ethylene glycol): a new stabilizer for silver nanoparticles
Beilstein J. Nanotechnol. 2017, 8, 627–635, doi:10.3762/bjnano.8.67
- be desirable (such as situations, where thiols may form thiyl radicals leading to protein degradation and cause diseases such as cancer) [34][35]. Hence, there is an interest in alternative anchoring groups with a similar or better anchoring efficiency. Among the possible candidates are the amine and
Investigation of the photocatalytic efficiency of tantalum alkoxy carboxylate-derived Ta2O5 nanoparticles in rhodamine B removal
Beilstein J. Nanotechnol. 2017, 8, 604–613, doi:10.3762/bjnano.8.65
- –hole pairs migrate to the surface and react with adsorbed water molecules or hydroxide ions to produce hydroxyl radicals. These hydroxyl radicals decompose the dye molecule into CO2 and water. The concentration of remaining dye in the solution is measured by using UV–vIS spectroscopy. The formula
- has also been investigated. Electron–hole pairs are generated during exposure to the UV radiation. These charge carriers produce radicals for the decomposition of the dye. The synthesized Ta2O5 nanoparticles removed rhodamine B efficiently under UV irradiation. It is observed that the photocatalytic
Tailoring bifunctional hybrid organic–inorganic nanoadsorbents by the choice of functional layer composition probed by adsorption of Cu2+ ions
Beilstein J. Nanotechnol. 2017, 8, 334–347, doi:10.3762/bjnano.8.36
- fluoroalkyl radicals, the gross compositions of Cu2+/Lig complexes are close to 1:1. Table S7 (Supporting Information File 1) provides parameters of the EPR spectra of copper(II) complexes formed on the surface of some carriers discussed in this paper, and Figure 7 represents the EPR spectra of some of these
- functional groups in the surface layers of nanoparticles. Consequently, IR spectroscopy confirmed the presence of a polysiloxane network containing 3-aminopropyl and methyl or fluorinated functional groups, as well as silanol groups, and alkyl radicals in the synthesized particles. Furthermore, all samples
- , Supporting Information File 1) indirectly indicate the “island-like” structure of the surface layer, where the “islands” of amino groups are surrounded with long hydrophobic radicals (Figure 9c,d) preventing the diffusion of ions to the centers of adsorption. Consequently, the introduction of methyl groups
Photocatalysis applications of some hybrid polymeric composites incorporating TiO2 nanoparticles and their combinations with SiO2/Fe2O3
Beilstein J. Nanotechnol. 2017, 8, 272–286, doi:10.3762/bjnano.8.30
- point, the degradation of organic compounds into CO2 and H2O begins. It is caused by reactive radicals (•OH, •O2−) produced through the interactions between the charge carriers from the surface with the adsorbed molecules (e.g., water and molecular oxygen) [25][54]. For this study, the
Nitrogen-doped twisted graphene grown on copper by atmospheric pressure CVD from a decane precursor
Beilstein J. Nanotechnol. 2017, 8, 145–158, doi:10.3762/bjnano.8.15
- ), a member of the homologous series of alkane hydrocarbons. n-Decane has a molecular mass approximately one order of magnitude greater than that of methane, which influences the growth kinetics of graphene. As a representative n-alkane, n-decane forms chains of radicals with a high reactive nature
- of the difference in ionic radii [16]. The radicals resulting from the decomposition of n-decane could lead to the decomposition of the nitrogen molecule, which in fact has one of the strongest binding energies. The resulting atomic nitrogen can be embedded into the graphene lattice. The n-decane was
- our case the efficient decomposition of nitrogen occurs due to the presence of hydrocarbon in the reactive mixture. Indeed, as it was shown by C. P. Fenimore, carbon (•C) or hydrocarbon (•CxHy) radicals may attack on nitrogen molecules [65]. The endothermicity of such a reaction can be an order of
Layered composites of PEDOT/PSS/nanoparticles and PEDOT/PSS/phthalocyanines as electron mediators for sensors and biosensors
Beilstein J. Nanotechnol. 2016, 7, 1948–1959, doi:10.3762/bjnano.7.186
- quinone, whereas laccase catalyzes the oxidation of a larger variety of aromatic compounds such as substituted mono- and poly-phenols, with subsequent formation of radicals, which are converted to quinones in the second stage of the oxidation [19]. Tyrosinase (Tyr) and laccase (Lac) must be combined with
Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures
Beilstein J. Nanotechnol. 2016, 7, 1684–1697, doi:10.3762/bjnano.7.161
- electrons from graphene can react with O2 and H+ ions to produce H2O2, which further decomposes in the presence of light to generate hydroxyl radicals (•OH) [67]. Also ZnO is inactive under visible light, so hole formation takes place only in the VB of CdS. As the VB edge of CdS is more negative than the
- standard redox potential of •OH/OH− (2.38 eV vs NHE) and •OH/H2O (2.72 eV vs NHE), •OH cannot be generated by reacting with H2O molecules. The •OH radicals are responsible for the dye degradation into CO2 and H2O [68][69]. The enhanced photocatalytic activity of the RGO-supported CdS–ZnO nanocomposite
High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis
Beilstein J. Nanotechnol. 2016, 7, 1338–1349, doi:10.3762/bjnano.7.125
- can be trapped by water and oxygen to generate hydroxyl •OH and superoxide O2•− radicals, respectively. These highly oxidizing species are responsible of the conversion of organic compounds into carbon dioxide, water, and inorganic salts. Zinc oxide (ZnO) is one of the most widely investigated
- min at pH 10 and 12, respectively). The high photocatalytic activity of the Ce-doped ZnO rods at basic pH may be attributed to the increased concentration of hydroxy anions that facilitate the photogeneration of hydroxy •OH radicals (−OH + h+ → •OH), thus enhancing the photocatalytic degradation
- photocatalyst is only weakly sensitive to salts commonly present in wastewater. Noteworthy is also that the Cl− and SO42− anions, which are well-known to be •OH radicals scavengers, have no detrimental effect on the photocatalytic activity. Transition metal salts used at 100 µM concentration like ZnCl2 or FeCl3
Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels
Beilstein J. Nanotechnol. 2016, 7, 675–684, doi:10.3762/bjnano.7.60
- epithelial A549 cells due to H2O2 and OH radicals caused by Cr(VI) [74]. From this prospective, the unclear mechanism behind the effect of NPs on the tight junction should never be considered to have only one reason, i.e., either the phosphorylation of core proteins or the oxidative stress on those proteins
Unraveling the neurotoxicity of titanium dioxide nanoparticles: focusing on molecular mechanisms
Beilstein J. Nanotechnol. 2016, 7, 645–654, doi:10.3762/bjnano.7.57
- injure tissues and organs, and is often associated with diseases and aging. Meanwhile, oxidative stress, caused by NPs, is the most important and widely accepted mechanism of nano-neurotoxicity. ROS, such as superoxide, hydrogen peroxide, and hydroxyl radicals, are natural products of the regular oxygen
- metabolism [15][16]. However, these free radicals can interact within biological systems, resulting in oxidative damage to the organism. These harmful effects can be counteracted by biological antioxidants, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), the expression
Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles
Beilstein J. Nanotechnol. 2016, 7, 630–636, doi:10.3762/bjnano.7.55
- , which together with the negative influence of OH radicals on the IR transmissions makes the development of new composites necessary. The aim of our work was to use the previously developed method of a water-free, low-temperature (below 230 °С) synthesis of rare-earth oxide nanoparticles from their
Novel roles for well-known players: from tobacco mosaic virus pests to enzymatically active assemblies
Beilstein J. Nanotechnol. 2016, 7, 613–629, doi:10.3762/bjnano.7.54
- were analyzed in colorimetric assays, detecting the generation of ABTS* radicals (Figure 6). Equal enzyme input amounts were applied into plate wells coated with (i) either fully assembled biotinylated TMVCys/Bio adapter sticks, or (ii) released lower-order CPCys/Bio aggregates, (iii) or stoichiometric
- these layouts using different adapter concentrations, applying the same [SA]-GOx/[SA]-HRP input for colorimetric glucose detection via formation of ABTS* radicals (absorption maximum at λ = 405 nm). TMV adapter templates support the immobilization of substantially increased enzyme activities. C: TMV
Comparison of the interactions of daunorubicin in a free form and attached to single-walled carbon nanotubes with model lipid membranes
Beilstein J. Nanotechnol. 2016, 7, 524–532, doi:10.3762/bjnano.7.46
- -induced heart failure, which is mainly associated with the process of the reactive oxygen species formation as well as the formation of hydroxyl radicals by free iron cations in the Fenton reaction [4]. Therefore, numerous studies focus on the application of different drug delivery systems (DDS) to
Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers: 2D followed by 3D growth
Beilstein J. Nanotechnol. 2015, 6, 2406–2411, doi:10.3762/bjnano.6.247
- induces the radiolysis of water. This results in the formation of various radicals (e.g., H•, HO•, e−aq). In the presence of a radical scavenger, H• and e−aq induce reduction of the metal ions into atoms that further aggregate in the solution to form metallic clusters. Usually γ rays or electrons [3] and
- (Millipore system, 18 MΩ·cm) at a silver concentration of 1.5·10−4 mol·L−1. Ethanol (CH3CH2OH) was added at a concentration of 0.2 mol·L−1 as a radical scavenger [15]. Indeed, irradiation of deoxygenated water leads to the formation of three radicals, HO•, H• and hydrated electrons, e−aq. By addition of
Green and energy-efficient methods for the production of metallic nanoparticles
Beilstein J. Nanotechnol. 2015, 6, 2354–2376, doi:10.3762/bjnano.6.243
Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties
Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235
- structure. The pure hexagonal phase was obtained at reaction temperatures ≥ 350 °C and annealing times above 1 h. To generate free radicals such as singlet oxygen (destructive to cancer cells) in biological experiments, the nanoparticles should emit photons at 660 nm to excite phthalocyanine, a typical
Effect of SiNx diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol–gel dip coating and reactive magnetron sputtering
Beilstein J. Nanotechnol. 2015, 6, 2039–2045, doi:10.3762/bjnano.6.207
- photocatalytic efficiency. The photobleaching of the OII dye in the presence of the catalyst was performed at neutral pH 7.2 during 2 h of UV–vis illumination. At neutral pH, the bleaching of OII was caused by photo-oxidation via formation of radicals and/or a UV-induced modification of the surface, leading to
Nitrogen-doped graphene films from chemical vapor deposition of pyridine: influence of process parameters on the electrical and optical properties
Beilstein J. Nanotechnol. 2015, 6, 2028–2038, doi:10.3762/bjnano.6.206
- evidence of oxidation [32]. Ethanol is known to decompose during CVD into oxygen-carrying and hydrocarbon molecules or radicals: Below a certain temperature, some of the oxygen atoms or groups might bind to defects, grains or edges [33]. Likewise, in the case of pyridine-CVD, the temperature can have a
The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors
Beilstein J. Nanotechnol. 2015, 6, 1904–1926, doi:10.3762/bjnano.6.194
- (IV) (CpPtMe3), which produced a similar mass spectrum during electron irradiation, despite the lack of the methyl group on the Cp ring. The conversion of the dissociated methyl radicals to the methane observed in the mass spectra is less clear as it could arise either from intra- or intermolecular
- reactions at the surface or from reactions of desorbed methyl radicals at the walls of the UHV chamber. While MeCpPtMe3 was found to desorb from the surface when it was heated to room temperature prior to electron irradiation, no compounds were found to desorb from the surface after electron irradiation
Temperature-dependent breakdown of hydrogen peroxide-treated ZnO and TiO2 nanoparticle agglomerates
Beilstein J. Nanotechnol. 2015, 6, 1897–1903, doi:10.3762/bjnano.6.193
- release of OH− or HO2 radicals. These radicals can remove impurities such as carbon and carbonate present on the surface and introduce hydroxyl groups (–OH) onto the surface [20][22][24]. Figure 2 and Figure 3 show the FTIR spectra of ZnO and TiO2 NPs before and after the H2O2 process, respectively
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